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Dear All I am a PhD student in Medical Gerontology and I would be very grateful for some help regarding a variable transformation problem. I have a continuous normally distributed variable (the risk factor) that I am trying to correlate with a continuous variable which has severe positive skewness (the outcome). I am using SPSS 16.0. The cubic fit method provides the best fit for the correlation between these two variables (RSqCubic = 0.6). Which means that as the risk factor increases linearly, the outcome increases exponentially, especially for the highest levels of the risk factor. In the correlation scatterplot there is almost a flat line until about mid values of the risk factor, followed by a sharp bend and a huge exponential increase. I would like to transform the risk factor so that it reflects linear increases in the outcome. What transformation should I use? What would be the formula I need to enter in the "Compute Variable" menu? Thank you very much in advance for your help Roman Romero